indicates acidity and a value of greater than 7 up to 14 indicates alkalinity. A value of 7 indicates
neutrality. If a corrosive material also meets the DOT criteria for classification as another hazard
(e.g., oxidizer, flammable, poison, etc.), a second label describing the additional hazard will be
affixed to the package. Many acids, when mixed with other acids, undergo hazardous reactions
that may, in turn, result in an explosion. For this reason, each material must be individually
evaluated to determine specific storage and/or safety requirements. An additional problem arises
in the case of material that is received in the warehouse, packaged and labeled for transportation
as corrosive, but that later loses its transportation label identity when the package is opened for
issue. Since only the outer package or wrapping was labeled corrosive for transportation, the
remaining units of the original package may not provide any indication that the material is
corrosive. For example, wet electric storage batteries, transported as corrosive, are embossed
with "EXPLOSIVE" and "POISON" warnings, but are not labeled as either for transportation.
When the outer packaging, bearing the "corrosive" label, is removed and discarded, care must be
taken to ensure that the material is treated as "corrosive" for storage purposes. Acetic acid, for
example, must be protected against physical damage and separated from oxidizing materials.
Storage near combustible materials must be avoided, and it must be kept above its freezing point
(62oF) to avoid rupture of carboys and glass containers. Other corrosives must be protected from
excessive heat. Organic acids should always be stored under automatic water sprinklers, whereas
sprinkler protection is not required for mineral acids. Combustible and oxidizing acids must be
appropriately segregated from each other and from other combustible or incompatible materials.
It should also be noted that, although a building or area may be dedicated to corrosive storage,
each material stored therein must be evaluated individually to determine its special storage and/or
safety requirements. Peroxyacetic acid, a strong oxidizer, for example, must never be stored on
wooden pallets since a leak may cause a fire or explosion. Hydrochloric acid, on the other hand,
should never be stored on a metal pallet since a leak may cause explosive hydrogen vapors to
form.
C. Applicable HCCs. The following HCCs should be stored in storage type C:
1. B1, Alkali, Corrosive, Inorganic.
2. B2, Alkali, Corrosive, Organic.
3. C1, Acid, Corrosive, Inorganic.
4. C2, Acid, Corrosive, Organic.
5. C4, Acid, Corrosive and Oxidizer, Inorganic.
6. C5, Acid, Corrosive and Oxidizer, Organic.
D. Storage Arrangement. Corrosives should be stored on pallets that are compatible with the
material being stored. Pallet racks or box pallets may be used to store corrosive solids. The
storage arrangement should permit constant surveillance and monitoring to detect leaking
containers. When corrosive materials are stacked in pallet racks, incompatible materials should
not be placed above or below each other. Acids (C1, C2, C4, C5) and alkalis (B1, B2) are
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